Graphene sheet comprising an intercalation compound and process of preparing the same

Abstract

A graphene sheet including an intercalation compound and 2 to about 300 unit graphene layers, wherein each of the unit graphene layers includes a polycyclic aromatic molecule in which a plurality of carbon atoms in the polycyclic aromatic molecule are covalently bonded to each other; and wherein the intercalation compound is interposed between the unit graphene layers.

1. A graphene sheet, comprising:
 an intercalation compound; and 
 2 to about 300 unit graphene layers, wherein 
 each of the unit graphene layers comprises a polycyclic aromatic molecule in which a plurality of carbon atoms in the polycyclic aromatic molecule are covalently bonded to each other; and wherein 
 the intercalation compound is interposed between the unit graphene layers. 
 
     
     
       2. A transparent electrode comprising a graphene sheet comprising an intercalation compound according to  claim 1 . 
     
     
       3. A solar cell comprising the transparent electrode of  claim 2 . 
     
     
       4. A conductive thin film comprising a graphene sheet comprising an intercalation compound according to  claim 1 . 
     
     
       5. A display device comprising the conductive thin film of  claim 4 . 
     
     
       6. The graphene sheet of  claim 1 , wherein the intercalation compound is regularly and periodically arranged. 
     
     
       7. The graphene sheet of  claim 1 , wherein about 1 to about 4 unit graphene layers are interposed between layers comprising the intercalation compound. 
     
     
       8. The graphene sheet of  claim 1 , wherein, the graphene sheet has a tetragonal structure and each of a width and a length of the graphene sheet is about 1 to about 1,000 millimeters. 
     
     
       9. The graphene sheet of  claim 1 , wherein the graphene sheet has a circular shape and a diameter of the graphene sheet is about 1 to about 1,000 millimeters. 
     
     
       10. The graphene sheet of  claim 1 , wherein the intercalation compound comprises at least one selected from the group consisting of an alkali metal, a halogen atom, a metal halide, an organic compound, an acidic compound, and any mixtures thereof. 
     
     
       11. The graphene sheet of  claim 1 , wherein the intercalation compound comprises at least one selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, fluorine, chlorine, bromine, iodine, IBr, ICl, AsF 5 , FeCl 2 , NiCl 2 , CoCl 2 , pentacene, tetracene, anthracene, 9,10-dichloroanthracene, 9,10-dibromoanthracene, acetic acid, nitric acid, hydrochloric acid, sulfuric acid, and any mixtures thereof. 
     
     
       12. The graphene sheet of  claim 1 , wherein a transmittance of the graphene sheet is about 5 to about 95 percent. 
     
     
       13. The graphene sheet of  claim 1 , wherein the graphene sheet is flexible. 
     
     
       14. A hydrogen storage medium comprising a graphene sheet comprising an intercalation compound according to  claim 1 . 
     
     
       15. An electrical device comprising a graphene sheet comprising an intercalation compound according to  claim 1 . 
     
     
       16. A process of preparing a graphene sheet comprising an intercalation compound, the process comprising:
 forming a graphene sheet; and 
 intercalating an intercalation compound into the graphene sheet using at least one method selected from the group consisting of 2-region vapor phase transport, constant temperature vapor phase transport, an electrochemical method, liquid phase intercalation, and any mixtures thereof. 
 
     
     
       17. The process of  claim 16 , wherein the forming the graphene sheet comprises:
 preparing a substrate having a graphitizing catalyst disposed on at least one surface of the substrate; 
 contacting a carbonaceous material with the substrate on which the graphitizing catalyst is disposed; and 
 heat treating the carbonaceous material and the graphitizing catalyst in an inert or a reducing atmosphere to form graphene. 
 
     
     
       18. The process of  claim 17 , wherein the carbonaceous material is selected from the group consisting of a carbon-containing polymer, a gaseous carbonaceous material, a liquid carbonaceous material, and any mixtures thereof. 
     
     
       19. The process of  claim 17 , wherein the graphitizing catalyst has a single crystalline structure. 
     
     
       20. The process of  claim 17 , wherein the contacting the carbonaceous material with the substrate is performed using at least one method selected from the group consisting of:
 coating the carbonaceous material on the substrate on which the graphitizing catalyst is disposed, wherein the carbonaceous material is a carbon containing polymer; 
 supplying the carbonaceous material onto the substrate on which the graphitizing catalyst is disposed, wherein the carbonaceous material is a gaseous carbonaceous material; and 
 immersing the substrate on which the graphitizing catalyst is disposed in the carbonaceous material to form an immersed substrate, and pre-heat-treating the immersed substrate, wherein the carbonaceous material is a liquid carbonaceous material 
 and any combinations thereof. 
 
     
     
       21. The process of  claim 17 , wherein the graphitizing catalyst comprises at least one selected from the group consisting of Ni, Co, Fe, Pt, Au, Al, Cr, Cu, Mg, Mn, Mo, Rh, Si, Ta, Ti, W, U, V, Zr, and any mixtures thereof. 
     
     
       22. The process of  claim 17 , wherein the heat treatment is performed at a temperature of about 400 to about 2,000° C. for about 0.1 to about 10 hours. 
     
     
       23. The process of  claim 17 , further comprising removing the graphitizing catalyst by acid treatment after the heat treatment. 
     
     
       24. The process of  claim 16 , wherein the 2-region vapor phase transport comprises:
 disposing the graphene sheet in a first chamber of a reactor and disposing the intercalation compound in a second chamber of the reactor, wherein the first chamber and the second chamber are connected to each other through a pathway; and 
 independently heating each of the first chamber and the second chamber. 
 
     
     
       25. The process of  claim 16 , wherein the constant temperature vapor phase transport comprises supplying a vapor phase intercalation compound into a chamber in which the graphene sheet is disposed, wherein the temperature of the chamber is maintained at a constant temperature. 
     
     
       26. The process of  claim 16 , wherein the liquid phase intercalation comprises immersing the graphene sheet in a liquid phase intercalation compound or in a solution of an intercalation compound to form an intercalated graphene sheet, and drying the intercalated graphene sheet. 
     
     
       27. The process of  claim 16 , wherein the electrochemical method comprises intercalating the intercalation compound into the graphene sheet by electrolysis in an electrolyte using the graphene sheet as an electrode and the intercalation compound as a counter electrode. 
     
     
       28. The process of  claim 16 , wherein at least two methods selected from the group consisting of 2-region vapor phase transport, constant temperature vapor phase transport, an electrochemical method, and liquid phase intercalation are sequentially performed. 
     
     
       29. The process of  claim 16 , wherein the intercalation compound comprises at least one selected from the group consisting of an alkali metal, a halogen atom, a metal halide, an organic compound, an acidic compound, and any mixtures thereof. 
     
     
       30. A process of preparing a graphene sheet comprising an intercalation compound, the process comprising:
 intercalating an intercalation compound into graphite using at least one method selected from the group consisting of 2-region vapor phase transport, constant temperature vapor phase transport, an electrochemical method, and liquid phase intercalation; 
 mechanically cutting the graphite into which the intercalation compound is intercalated; and 
 repeating the cutting of the graphite to obtain a graphene sheet comprising an intercalation compound. 
 
     
     
       31. The process of  claim 30 , wherein the mechanically cutting comprises separating graphite using an adhesive tape.